Beneficial control of energy balance in periparturient cattle

ABSTRACT

The present invention provides a method for beneficial control of body condition and dietary energy balance in dairy cattle during colostrum milk production. An important aspect of the beneficial control is the provision of a feedstock which has a supplemented content of trans-10, cis-12 conjugated linoleic acid derivative having rumen-bypass properties. The ingested quantity of CLA derivative ingredient per cow is effective for lowering and maintaining the fat content of colostrum milk in the range between about 4-6 weight percent and for increasing milk yield. The presence of cis-9, trans-11 conjugated linoleic acid structural isomer in an invention feedstock is minimized, because it counteracts the beneficial effects of the trans-10, cis-12 conjugated linoleic acid structural isomer, such as reduction in milk yield.

BACKGROUND OF THE INVENTION

[0001] This invention generally relates to dietary factors with respectto postpartum dairy cattle nutrition. More specifically, this inventionrelates to beneficial control of body condition and energy balance indairy cattle during colostrum milk production after calving.

[0002] There are numerous dairy science publications which elaboratetheory and practice in connection with the biology of dairy cattleduring a prepartum-postpartum transition period.

[0003] The time span from three weeks before to three weeks after dairycattle parturition (i.e., the “periparturient” period) is criticallyimportant to health, production, and profitability of the cows. Mostinfectious diseases and metabolic disorders occur during thisperiparturient period, such as milk fever, ketosis, retained fetalmembranes, metritis, and displaced abomasum. Immunosuppression duringthe periparturient period leads to increased susceptibility to mastitis.

[0004] Occurrences of periparturient diseases and disorders in dairycattle have lasting negative impacts on milk yield during lactation, inaddition to the cost of lost saleable milk during treatment for adisorder and the cost of veterinary care. Extreme negative energybalance and extensive loss of body condition during the periparturientperiod also can challenge subsequent reproductive success.

[0005] Relatively little is known about fundamental biological processesduring this dairy cattle prepartum-postpartum transition period.Knowledge of key control points in hepatic metabolism of long-chainfatty acids is lacking, as is an insight into the metabolic effects ofhormones, growth factors, and cytokines that mediate stress. Increasedunderstanding of the biology of the periparturient period should serveto decrease lactating cattle health problems and increase profitabilityof dairy operations.

[0006] During the early lactation phase of postpartum cows, there is asevere negative energy balance which stresses the body condition andpredisposes the animals to ketosis and reduced productive performance.An important factor in the early lactation energy drain effect is theproduction of colostrum milk with a milk fat content as high as tenweight percent.

[0007] Of particular interest with respect to the present invention arereported studies in connection with nutrition as the predominantenvironmental factor affecting milk fat content during lactation, andthe role of nutrition as a practical vehicle for altering the yield andcomposition of milk fat. The effect of feedstock on the yield andcomposition of milk fat is described in publications which include J.Dairy Sci., 72, 2801 (1989); J. Dairy Sci., 74, 3244 (1991); and J.Dairy Sci., 76, 1753 (1993).

[0008] There is continuing interest in the development of new andimproved supplemented feedstocks and protocols for enhancing the healthand productivity of dairy cattle during the periparturient period.

[0009] Accordingly, it is an object of this invention to provide aformulated high-energy feedstock for beneficial feeding of dairy cattleduring the periparturient period.

[0010] It is another object of this invention to provide a feedstockwhich is adapted for decreasing the dietary energy balance deficit inpostpartum cattle, and for reducing the milk fat content of colostrummilk during initial lactation.

[0011] It is another object of this invention to provide a method forbeneficial control of body condition and dietary energy balance in dairycattle during colostrum milk production after calving.

[0012] It is a further object of this invention to provide a method forincreasing the milk yield over the lactating cycle of dairy cattle bybeneficial control of dietary energy partitioning.

[0013] Other objects and advantages of the present invention shallbecome apparent from the accompanying description and example.

DESCRIPTION OF THE INVENTION

[0014] One or more objects of the present invention are accomplished bythe provision of a method for beneficial control of body condition anddietary energy partition for increased milk yield in dairy cattle duringcolostrum milk production after calving, which method comprises feedingthe postpartum dairy cattle with a feedstock comprising (1) ahigh-energy nutritionally-balanced ration adapted for postpartumlactating dairy cattle, and having a dietary cation-anion difference(DCAD) between about 0-60 meq/100 g dietary DM; and (2) conjugatedlinoleic acid derivative having rumen-bypass properties, and provided ina daily quantity which is effective for lowering and maintaining themilk fat content of colostrum milk in the range between about 4-6 weightpercent.

[0015] The invention method of feeding the postpartum dairy cattle iseffective for managing a dietary energy balance deficit of less thanabout −10 Mcal/cow/day during colostrum production.

[0016] In a further embodiment the present invention provides afeedstock for beneficial control of dietary energy balance deficit inpostpartum dairy cattle at a level less than about −10 Mcal/cow/dayduring colostrum milk production, which feedstock comprises (1) ahigh-energy nutritionally-balanced ration adapted for postpartumlactating dairy cattle, and having a dietary cation-anion difference(DCAD) between about 0-60 meq/100 g dietary DM; and (2) between about0.3-1 gram/kg dietary DM of conjugated linoleic acid derivative havingrumen-bypass properties, and which derivative comprises trans-10, cis-12structural isomer, and which contains less than about 20 weight percentof cis-9, trans-11 structural isomer.

[0017] The high-energy nutritionally balanced ration component of aninvention feedstock is custom formulated for intensive feeding of dairycattle after calving. A ration component is isocaloric andisonitrogenous, and preferably includes a content of slow-releasedegradable nitrogen source for efficient rumen fermentation, and acontent of rumen-bypass protein.

[0018] A typical ration can include about 14-20 percent of crudeprotein, about 30-40 percent of rumen-bypass protein, and about 1-12percent of slow-release degradable nitrogen source, based on dry matter.The net carbohydrate and protein system of the ration component of thefeedstock is maintained in optimal balance.

[0019] The following basal ration illustrates the nutrient constituentsof a feedstock suitable for the practice of the present invention: DryNutrients Weight % Soybean meal (49% CP) 3.25 Oats 9.30 Molasses 2.30Min/vit 1.40 Grass hay 16.00 Bypass protein 3.00 Slow-release NPN 2.25Corn silage 16.00 Cracked corn 25.00 Hayage 19.00

[0020] In the transition period before calving, the feedstock for dairycattle preferably has a dietary cation-anion difference (DCAD) valuebetween about −15 and zero meq/100 g dietary DM.

[0021] After calving, an invention feedstock preferably has a dietarycation-anion difference (DCAD) value between about 0-60 meq/100 gdietary DM, to suppress metabolic disorders such as the onset ofhypocalcemia and metabolic acidosis in the lactating dairy cattle.

[0022] The term “dietary cation-anion difference (DCAD)” was coined torepresent the mathematical calculation (W. K. Sanchez and D. K. Beede.Page 31, Proc. Florida Rum. Nutr. Conf. Univ. of Florida. 1991).Expressed in its fullest form, DCAD is written as follows:

meq[(Na⁺+K⁺+Ca⁺²+Mg⁺²)−(Cl⁻+SO₄ ⁻²+PO₄ ⁻³)]/100 g of dietary dry matter(DM).

[0023] A problem with including the multivalent macrominerals (Ca, Mg, Pand S) in the DCAD expression for ruminants relates to the variable andincomplete bioavailability of these ions compared to Na, K and Cl. Theexpression employed most often in ruminant nutrition is the monovalentcation-anion difference:

meq(Na⁺+K⁺−Cl⁻)/100 g dietary DM

[0024] Because of the additional use of sulfate salts in dairy cattlerations, the expression that has gained most acceptance in lactating cownutrition, and practiced in the present invention, is as follows:

meq(Na⁺+K⁺)−(Cl⁻+SO₄ ⁻²)/100 g dietary DM

[0025] An essentially required ingredient of a present inventionfeedstock is a quantity of rumen-bypass conjugated linoleic acid (CLA)derivative which is effective for lowering and maintaining the milk fatcontent of colostrum milk in the range between about 4-6 weight percent.An effective rumen-bypass ingredient comprises trans-10, cis-12conjugated linoleic acid derivative.

[0026] The quantity of conjugated linoleic acid derivative havingrumen-bypass properties in a feedstock typically is between about 0.3-1ram CLA/kg dietary DM. Preferably the feeding regimen is at a rate whichprovides between about 5-15 grams CLA/cow/day; and which effectivelyprovides between about 4-12 grams CLA/cow/day in the cow intestine oftrans-10, cis-12 conjugated linoleic acid rumen-bypass derivative duringthe colostrum milk production period. Normally the CLA additive is fedto the dairy cattle from about 5-10 days prepartum to about 35-40 dayspostpartum.

[0027] With respect to the inhibition of fat synthesis and the loweringof the fat content of colostrum milk, trans-10, cis-12 conjugatedlinoleic acid and cis-8, trans-10 conjugated linoleic acid derivativesare effective for reducing the activities of key lipogenic enzymes, andthereby decreasing rates of lipogenesis. The cis-9, trans-11 linoleicacid isomer has little or no effect on the expression of fat synthetasein lactating cattle.

[0028] An important aspect of the present invention is an increase inmilk yield in dairy cattle which is directly attributable to themetabolic effect of conjugated linoleic acid such as the trans-10,cis-12 structural isomer. The milk yield over the lactating cycle of thedairy cattle can be increased by about 14-22 percent with the trans-10,cis-12 conjugated linoleic acid structural isomer having rumen-bypassproperties.

[0029] Optimal milk yields are achieved when the added conjugatedlinoleic acid directive in a feedstock contains less than about 20weight percent of cis-9, trans-11 conjugated linoleic acid structuralisomer, and preferably less than about 5 weight percent. Thecounter-productive milk yield effect in dairy cattle of cis-9, trans-11conjugated linoleic acid appears to be related to the cell proliferationregulatory properties of this structural isomer.

[0030] When the mammary gland develops prior to first calving andimmediately prior to each subsequent calving (and the ensuinglactation), the gland is composed of a certain number of “stem cells”.These stem cells are the undifferentiated cells of the mammary glandthat will differentiate into secretory cells known as mammocytes. Thesecells go through a life cycle, and at this undifferentiated stage theyresemble a cancer cell which is an undifferentiated or de-differentiatedcell-type. High milk production depends on having a large number ofthese stem cells divide and differentiate into functional mammocytes.

[0031] Cis-9, trans-11 conjugated linoleic acid has anti-carcinogenicproperties. A cancer cell is undifferentiated, and has unregulatedgrowth. Cis-9, trans-11 conjugated acid can impart growth regulation tocancer cells. It is believed that by a similar regulatory mechanismcis-9, trans-11 congugated linoleic acid inhibits mammary stem cellsfrom dividing and differentiating into functional mammocytes. Thiseffect is countercurrent to the beneficial increase in milk yieldobtained with trans-10, cis-12 conjugated linoleic acid.

[0032] To achieve its beneficial effects as a feedstock additive, it isessential that the conjugated linoleic acid derivative has rumen-bypasscapability. The conjugated linoleic acid derivative can be in the formof CLA alkaline earth metal salt, such as calcium and/or magnesium salt.The derivative also can be in the form of CLA amide, in which the amidenitrogen is substituted with hydrogen and/or aliphatic radicals. Fattyacid salts and amides having rumen-bypass properties are described inpublications such as U.S. Pat. Nos. 4,642,317; 4,826,694; 5,391,788;5,425,693; 5,456,927; 5,496,572; 5,547,686; 5,670,191; 5,874,102; andthe like, incorporated by reference.

[0033] Optionally, the CLA can be rumen-protected when in the form ofpolymer-encapsulated matrix. Typically, the polymer is a continuous filmcoating that functions as an impermeable barrier under rumen conditions.Suitable polymers include gum arabic, polyvinylpyrrolidone,polyacrylamide, polyvinyl acetate, cellulose acetate, zein, shellac, andthe like.

[0034] An optional biologically active ingredient can be included in aninvention feedstock in an effective quantity between about 0.05-20weight percent, based on the dry matter weight of the feedstock. It canbe selected from a broad variety of nutrients and medicaments, either asa single component or a mixture of components, which are illustrated bythe following listing of active ingredients:

[0035] 1. acid-base buffers which typically are selected from carbonateand phosphate salts, and which serve to moderate and control the dietaryanion-cation difference (DCAD) of an invention feedstock, and to reducethe rate and extent of biohydrogenation of free fatty acids in therumen.

[0036] 2. sugars and complex carbohydrates which include bothwater-soluble and water-insoluble monosaccharides, disaccharides andpolysaccharides.

[0037] Cane molasses is a byproduct from the extraction of sucrose fromsugar cane. It is commercially available at standard 79.5° Brixconcentration, which has a water content of about 21 weight percent, anda sugar content of 50 weight percent. Sugar beet byproducts also areavailable as low cost carbohydrate sources.

[0038] Whey is a byproduct of the dairy industry. The whey is a dilutesolution of lactalbumin, lactose, fats, and the soluble inorganics frommilk. Dried whey solids typically have the following composition:Protein 12.0% Fat 0.7% Lactose 60.0% Phosphorus 0.79% Calcium 0.874% Ash9.7%

[0039] Another source of carbohydrate is derived from the pulp and paperindustry which produces large quantities of byproduct lignin sulfonatesfrom wood during the sulfite pulping process. The carbohydrate byproductis a constituent of the spent sulfite liquor.

[0040] 3. aminoacid ingredients either singly or in combination whichinclude arginine, histidine, isoleucine, leucine, lysine, methionine,phenylalanine, threonine, tryptophan, valine, tyrosine ethyl HCl,alanine, aspartic acid, sodium glutamate, glycine, proline, serine,cysteine ethyl HCl, and the like, and analogs and salts thereof.

[0041] 4. vitamin ingredients either singly or in combination whichinclude thiamine HCI, riboflavin, pyridoxine HCl, niacin, niacinamide,inositol, choline chloride, calcium pantothenate, biotin, folic acid,ascorbic acid, vitamin B₁₂, p-aminobenzoic acid, vitamin A acetate,vitamin K, vitamin D, vitamin E, and the like.

[0042] Trace element ingredients include compounds of cobalt, copper,manganese, iron, zinc, tin, nickel, chromium, molybdenum, iodine,silicon, vanadium and selenium.

[0043] 5. protein ingredients as obtained from sources such as driedblood or meat meal, dried and sterilized animal and poultry manure, fishmeal, liquid or powdered egg, fish solubles, cell cream, soybean meal,cottonseed meal, canola meal, and the like.

[0044] Protein ingredients include non-protein nitrogen compounds suchas urea, biuret, ammonium phosphate, and the like.

[0045] 6. antioxidants as illustrated by butylated hydroxyanisole,butylated hydroxytoluene, tocopherol, tertiary-butylhydroquinone, propylgallate, and ethoxyquin; and suitable preservatives include sodiumsorbate, potassium sorbate, sodium benzoate, propionic acid,α-hydroxybutyric acid, and the like.

[0046] 7. suspension stabilizing agents which preferably are selectedfrom nonionic surfactants, hydrocolloids and cellulose ethers. Thesetypes of chemical agents are illustrated by polyethylene oxidecondensates of phenols, C₈-C₂₂ alcohols and amines; ethylene oxidereaction products with fatty acid partial esters of hexitans;alkylarylpolyoxyethylene glycol phosphate esters; gum arabic; carob beangum; tragacanth gum; ammonium, sodium, potassium and calcium alginates;glycol alginates; xanthan gum; potato agar; alkylcellulose;hydroxyalkylcellulose; carboxyalkylcellulose; and the like.

[0047] Practice of the present invention embodiments provides manifoldadvantages for managing postpartum cattle.

[0048] There is increased feed intake, which helps minimize thenutritional deficit during colostrum milk production after calving.

[0049] Dairy cattle suffer less stress and body weight loss, and thereis less susceptability to ketosis and hypocalcemia.

[0050] The milk fat content of colostrum milk produced by postpartumdairy cattle is lowered and maintained in the range between about 4-6weight percent.

[0051] Postpartum dairy cattle can have an onset dietary energy balancedeficit level improved to less than about −5 Mcal/cow/day within about3-5 weeks after lactation onset.

[0052] In accordance with the present invention postpartum dairy cattleachieve an increase in first lactation milk production and lifetimemilk, and can manifest improved reproductive performance.

[0053] The following Example is further illustrative of the presentinvention. The components and specific ingredients are presented asbeing typical, and various modifications can be derived in view of theforegoing disclosure within the scope of the invention.

EXAMPLE

[0054] The Example illustrates the health benefits and increased milkyield obtained by feeding postpartum dairy cattle with rumen-bypasstrans-10, cis-12 conjugated linoleic acid derivative in accordance withthe present invention.

[0055] One hundred and twenty Holstein cows who were to begin theirsecond or greater lactation are randomly selected to receive one of fourConjugated Linoleic Acid (CLA) supplementation regimens. Control cowsreceive no supplemental CLA (0 CLA), cows offered Treatment 1 receivethe cis-9, trans-11 CLA isomer (9,11 CLA), cows offered Treatment 2receive the trans-10, cis-12 CLA isomer (10,12 CLA) and cows offeredTreatment 3 receive both isomers in a 50:50 mix (mixed CLA).

[0056] Isomers of CLA are obtained at 85% purity and are converted totheir amide form (unsubstituted) for a rumen bypass rate of 65%. Theremaining 15% of the 85% pure CLA isomers are the other isomers of CLA.Treatments 1 and 2 are formulated to deliver 7 grams of each CLA isomerper cow/day at the intestinal level. Therefore, 13 g/cow/day of therespective CLA amides are included in the daily rations offered as TotalMixed Rations (TMR) (i.e., 13 g CLA amide×85% purity×65% rumenbypass=7.18 g intestinal CLA isomer). Treatment 3 is formulated todeliver 7 grams of both isomers per cow per day in the intestineresulting in a 26 g supplement.

[0057] Cows are fed their CLA treatments beginning 7 days prepartum andremain on the supplement until 35 days postpartum. The pre- andpostpartum diets are listed in Tables 1 and 2. To maintain the dietsisoenergetic with equal amounts of added fat to the diets, the CLAamides are substituted for Megalac (calcium salts of palm fatty acids).Postpartum diets are offered immediately postpartum.

[0058] Prepartum diets are formulated to meet or exceed NRC (2000)requirements at a daily intake of 10.6 kg of DM. This is done to assurethat all feed is consumed in a 24-hour period. Postpartum diets are alsoformulated to meet or exceed requirements for a cow producing (ca.) 45kg of milk daily at ad libitum consumption of DM.

[0059] Cows are milked four times per day to assure maximum expressionof production potential and are housed and fed in individual tie-stallsto obtain individual estimates of DMI.

[0060] At day 15 postpartum five of the 30 cows per treatment aresacrificed with their mammary glands excised for analysis of totalparenchymal DNA and the RNA-to-DNA ratio.

[0061] Other measurements include: Start-up milk production (defined ascolostrum milk secreted in the first 24 hours postpartum) analyzed formilk fat and fatty acid composition; Daily milk production andcomposition (total fat and protein); Daily dry matter intake (DMI);Calculated net energy balance defined as net energy intake minus netenergy secreted in milk expressed in megacalories (Mcal) per day.

RESULTS

[0062] All feed is consumed in the prepartum period on a daily basisexcept on days 2 prepartum through day of calving. Intake of DM is toovariable between groups to determine any significant differences forthese days.

[0063] Postpartum DMI is not significantly different between treatmentsand begin at 11.1 kg/d and rise up to 22 kg/d by day-35 postpartum.Therefore, there are no differences in net energy intake between dietarytreatments.

[0064] Total parenchymal DNA is (compared to 0 CLA group) 18% lower, 8%greater and 10% lower for the 9,11 CLA, the 10,12 CLA, and the mixed CLAgroups, respectively. The 10,12 CLA group is significantly (P<0.01)higher than the other two CLA supplemented cows but not different fromcontrol cows. Ratio of RNA-to-DNA is lowest for the mixed CLA and 10,12CLA groups (P<0.05).

[0065] Table 3 summarizes production parameters for all groups.Calculated average energy balance postpartum is actual daily DMI minusactual daily milk energy outputs.

INVENTION ADVANTAGES

[0066] One important attribute of the 10,12 CLA isomer is to reducefatty acid synthesis. This is obvious from the total amount of milk fatproduced and from the ratio of short plus medium chain fattyacids-to-long chain fatty acids in milk fat from Table 3. Cowssupplemented with 10,12 CLA and with the mixed CLA both reduce milk fatprimarily by slowing down mammary synthesis of the short and mediumchain fatty acids resulting in a majority of the milk fat arising fromlong chain fatty acids circulating in the blood. Further evidence is thereduced RNA-to-DNA ratio in both groups receiving the 10,12 CLA isomer.The reduced RNA per cell is likely related to the enzyme systemassociated with milk fatty acid synthesis. In the first 24 hourspostpartum, the reduction of fat corrected milk production results inanimals having a positive energy balance when they are primarilyconsuming the 10,12 CLA isomer, likely avoiding excessive body fatmobilization during this critical period. By avoiding the negativeenergy balance in this first 24 hours postpartum the cows supplementedwith the 10,12 CLA isomer are able to produce more total milk and fatcorrected milk than all other groups, including the group fed the 10,12CLA plus 9,11 CLA isomers.

[0067] The 9,11 CLA isomer is attributed with reduced incidence of theinduction and proliferation of cancer cells. Cancer cells are dividingcells with similar properties to stem cells that mistakenlydifferentiate into cells that cannot control their growth. As themammary glands contain a population of undifferentiated cells (stemcells) that must differentiate into mammocytes (milk secretory cells) inthe periparturient period, it is hypothesized that the 9,11 CLA isomerprevents this differentiation process leading to less secretory cells inthe mammary gland when the isomer is present in high enough levels. Thishypothesis is supported by the lower amounts of DNA found in themammaries of both groups that received the 9,11 CLA isomer. TABLE 1Composition of prepartum diets in kg of DM/cow/day. Values inparentheses are expressed as a percentage of the total dietary DM.INGREDIENT 0 CLA 9, 11 CLA 10, 12 CLA MIXED CLA Alfalfa hay 2.0 2.0 2.02.0 (18.9) (18.9) (18.9) (18.9) Corn Silage 5.4 5.4 5.4 5.4 (50.9)(50.9) (50.9) (50.9) Ground Corn 1.8 1.8 1.8 1.8 (17.0) (17.0) (17.0)(17.0) Biochlor* 0.96 0.96 0.96 0.96 (9.06) (9.06) (9.06) (9.06)Megalac** 0.11 .097 .097 .084 (1.03) (0.92) (0.92) (0.79) CLA amide 0.013 .013 .026 supplement (0)  (0.12) (0.12) (0.25) Vit-Min premix 0.330.33 0.33 0.33 (3.11) (3.11) (3.11) (3.11) NUTRIENT Crude protein, %15.8 15.8 15.8 15.8 Nel (Mcal/kg) 1.67 1.67 1.67 1.67 NDF, % 36 36 36 36DCAD, meq/100 g −8 −8 −8 −8

[0068] TABLE 2 Composition of postpartum diets in kg of DM/cow/day.Values in parentheses are expressed as a percentage of the total dietaryDM. INGREDIENT 0 CLA 9, 11 CLA 10, 12 CLA MIXED CLA Alfalfa hay 3.183.18 3.18 3.18 (13.35) (13.35) (13.35) (13.35) Corn silage 7.48 7.487.48 7.48 (31.46) (31.46) (31.46) (31.46) Soybean hulls 0.98 0.98 0.980.98 (4.12) (4.12 (4.12) (4.12) Ground corn 5.72 5.72 5.72 5.72 (24.05)(24.05) (24.05) (24.05) Soybean meal 1.80 1.80 1.80 1.80 (7.57) (7.57)(7.57) (7.57) Blood meal 0.36 0.36 0.36 0.36 (1.53) (1.53) (1.53) (1.53)Brewers grains, wet 1.66 1.66 1.66 1.66 (6.99) (6.99) (6.99) (6.99)Vit-Min premix 0.65 0.65 0.65 0.65 (2.72) (2.72) (2.72) (2.72)Fermenten* 0.91 0.91 0.91 0.91 (3.81) (3.81) (3.81) (3.81) Megalac**0.25 0.237 0.237 0.224 (1.05) (0.996) (0.996) (0.942) Megalac Plus**0.25 0.25 0.25 0.25 (1.05) (1.05) (1.05) (1.05) CLA amide 0 0.013 0.0130.026 supplement (0)  (0.055) (0.055) (0.11) Sodium Bicarbonate 0.350.35 0.35 0.35 (1.47) (1.47) (1.47) (1.47) Potassium 0.2 0.2 0.2 0.2Carbonate (0.84) (0.84) (0.84) (0.84) NUTRIENT Crude protein, % 18 18 1818 Nel (Mcal/kg) 1.85 1.85 1.85 1.85 NDF, % 30.2 30.2 30.2 30.2 DCAD,meq/100 g +42 +42 +42 +42

[0069] TABLE 3 Milk production statistics for the first 24 hourspostpartum startup milk (colostrum) and the average for the next 34 dayspostpartum. FCM (Fat Corrected Milk) is milk product corrected to a fatcontent of 4%. STATISTIC 0 CLA 9, 11 CLA 10, 12 CLA MIXED CLA Startupmilk (kg) 24.1lb 20.2a 25.3c 23.6b Startup milk fat % 8.6c 8.9c 4.9a6.1b Startup milk fat kg 1.73c 1.44b 1.15a 1.19a SCFA + MCFA: 25:75b28:72.b 12:88a 19:81a LCFA* Startup FCM (kg) 40.73d 35.05c 28.72a 31.03bCalculated energy −7.6a −3.6b +0.72d −0.88c balance at the end of day-1postpartum (Mcal) Milk (kg/d) 42.6b 40.2a 47.2d 44.8c Milk fat % 3.42a3.45a 2.99b 3.02b SCFA + MCFA: 56.44b 58.42b 39.61a 43.57a LCFA* Milkfat (kg/d) 1.11b 1.04a 1.11b 1.05a FCM (kg/d) 38.89b 36.88a 40.05c38.21b Calculated average −1.4c −1.1c −.21a −.72b energy blancepostpartum (Mcal/d)

What is claimed is:
 1. A method for beneficial control of body conditionand dietary energy partition for increased milk yield in dairy cattleduring colostrum milk production after calving, which method comprisesfeeding the postpartum dairy cattle with a feedstock comprising: (1) ahigh-energy nutritionally-balanced ration adapted for postpartumlactating dairy cattle, and having a dietary cation-anion difference(DCAD) value between about 0-60 meq/100 g dietary DM; and (2) congugatedlinoleic acid derivative having rumen-bypass properties, and provided ina daily quantity which is effective for lowering and maintaining themilk fat content of colostrum milk in the range between about 4-6 weightpercent.
 2. A method in accordance with claim 1 wherein the dietaryenergy balance deficit of the dairy cattle is less than about −10Mcal/cow/day during colostrum milk production.
 3. A method in accordancewith claim 1 wherein the ration has a content of rumen-bypass protein,and slow-release degradable nitrogen source for efficient rumenfermentation.
 4. A method in accordance with claim 1 wherein thequantity of effective congugated linoleic acid derivative in thefeedstock is in the range between about 0.3-1 gram CLA/kg dietary DM. 5.A method in accordance with claim 1 wherein the conjugated linoleic acidderivative is in the form of calcium salt and/or magnesium salt and/orcarboxylic acid amide and/or polymer-encapsulated matrix.
 6. A method inaccordance with claim 1 wherein the effective constituent of theconjugated linoleic acid derivative comprises trans-10, cis-12structural isomer, and wherein the conjugated linoleic acid derivativecomprises less than about 20 weight percent of cis-9, trans-11structural isomer.
 7. A method in accordance with claim 1 wherein thefeeding is at a rate which provides between about 5-15 grams CLA/cow/dayof effective conjugated linoleic acid derivative as sufficient forbeneficial control of body condition and dietary energy partition in thepostpartum dairy cattle.
 8. A method in accordance with claim 1 whereinthe feeding is at a rate which provides between about 4-12 grams/cow/dayin the cow intestine of trans-10, cis-12 conjugated linoleic acidrumen-bypass derivative.
 9. A method in accordance with claim 1 whereinthe milk yield over the lactating cycle of the dairy cattle is increasedbetween about 14-22 percent.
 10. A feedstock adapted for beneficialcontrol of the dietary energy balance deficit in postpartum dairy cattleat a level less than about 10 Mcal/cow/day during colostrum milkproduction, which feedstock comprises (1) a high-energynutritionally-balanced ration adapted for postpartum lactating dairycattle, and having a dietary cation-anion difference (DCAD) betweenabout 0-60 meq/100 g dietary DM; and (2) between about 0.3-1 gram/kgdietary DM of conjugated linoleic acid derivative having rumen-bypassproperties, and which deivative comprises trans-10, cis-12 structuralisomer, and which contains less than about 20 weight percent of cis-9,trans-11 structural isomer.
 11. A feedstock in accordance with claim 10wherein the conjugated linoleic acid derivative is in the form ofcalcium salt and/or magnesium salt and/or carboxylic acid amide and/orpolymer-encapsulated matrix.